T. H. Clark — A New Agelacrinitid. 



Aet. VIII. — A New Agelacrinitid from the Chazy of New 

 York; by Thomas H Clark. 



In 1919 I described an Agelacrinitid, Cameyella ray- 

 mondi, from the Trenton limestone at Martinsburg, N. Y. 

 This was of especial importance because, as was stated, 

 "so far as is known, this is the first agelacrinitid to be 

 found in the Ordovician rocks in New York State." 1 

 While collecting on Valcour Island, N. Y. last summer I 

 was fortunate enough to discover a specimen of the same 

 genus in the Chazy limestone. So far as I know, this is 

 the first Agelacrinitid to be reported from a horizon 

 lower than the Trenton in the United States. The dis- 

 covery of this specimen, for which the name Cameyella 

 valcour ensis is proposed, lengthens the range of these 

 fossils considerably. 



The specimen is small, incomplete, apparently free, 

 and somewhat deformed by having one side doubled 

 under. It shows all five rays, but parts of some of these 

 have been bent under by the crumpling of the specimen. 

 It is by no means well preserved, but fortunately it does 

 show that the supra-oral plates are both larger and of 

 different form than the lateral covering plates. A very 

 diligent search by Dr. Raymond and myself failed to 

 secure other specimens. 



The accompanying table illustrates the comparative 

 ranges of the species of Foerste's recently described 

 genera Cameyella and Isorophus, 2 as well as those of 

 Bather's genus Lebetodiscus, 3 the three genera of the 

 Agelacrinitidse that are represented in the Ordovician 

 rocks on this continent. Foerste remarked: "In Isoro- 

 phus the supra-oral plates differ only slightly from the 

 lateral covering plates of the rays, and the genus is re- 

 garded as more primitive in type. ' ' This last statement 

 should be regarded in the light of the fact that, of the 

 two genera, Cameyella is the older, and reached its full- 

 est development at the time when Isorophus was intro- 

 duced and apparently did not survive the maximum 

 development of that genus. 



1 Bull. Mus. Comp. Zool., vol. 63, No. 1, p. 11. 

 2 Bull. Sci. Lab. Denison Univ., Vol. 18, p. 341, 1916. 



3 Geol. Mag. 1908, Dec. V, Vol. 5, p. 550, pi. XXV. Reprinted in 

 "Studies in Edrioasteroidea, ' ' 1915. 



